<!DOCTYPE html>
<html lang="en"
      xmlns:th="http://www.thymeleaf.org">
<head>
    <meta charset="UTF-8">
    <title>hello</title>
</head>
<body>
<p style="background-color: darkseagreen">
    ${...}可以显示后台变量
</p>
<p th:text="${gre.greeting}"></p>
</body>
</html>